Background &Aims: Halitosis is described as unpleasant breath, regardless of its sources. There are several factors that cause halitosis. In most cases (80 -90%), it has intraoral origin and is one of the most frequent complaints that makes a patient to visit a dentist. The aim of this study was to determine the prevalence of oral halitosis and related oral problems among dental students.Materials & Methods: This cross-sectional study was conducted on 225 dental students. The samples completed forms and also intra oral examination was conducted with consideration of deep caries, redness and inflammation of the tonsils, periodontal disease, pericoronitis, and tongue coating. Then organoleptic test was performed for all patients. The ones whose organoleptic test scores was equal or greater than 2 were considered with halitosis. Descriptive statistics and statistical tests, chi-square, Mann-Whitney, and logistic regression modeling were used and data analysis was performed using SPSS 21.Results: Out of 225 samples enrolled, 151 (67.1%) patients were suffering from halitosis. Tongue coating (p <0.0001), pericoronitis (p = 0.023) and tonsillitis (p = 0.025) had significant relationship with halitosis but decay and periodontal disease didn’t have.Conclusion: Tongue coating was the most powerful association with halitosis, redness and inflammation of the tonsils and pericoronitis was also an important factor affecting halitosis.